JP2018177525A - Sheet feeding device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeding device capable of corresponding to feeding of sheets of wide range of basis weight and size while reducing skew of the sheet, and to provide an image forming device comprising the same.SOLUTION: This device comprises: an intermediate plate on which sheets are loaded; a pickup roller 110 which applies a feeding force in a sheet feeding direction by contacting to the sheet loaded on the intermediate plate to feed the sheet; A side regulation guide 117R which has a contact surface 117b capable of contacting to an end part in a width direction orthogonal to the sheet feeding direction of the sheet loaded on the intermediate plate to regulate the position of the end part; and an obliquely feeding roller 121 which is provided independently of the pickup roller 110 and contacts to the sheet loaded on the intermediate plate, to apply a force so that the sheet fed by the pickup roller 110 rotates.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a sheet feeding apparatus for feeding a sheet and an image forming apparatus provided with the sheet feeding apparatus.

  Generally, in an image forming apparatus such as a printer, a sheet accommodated in a cassette is fed by a pickup roller, and an image is formed on the fed sheet in an image forming unit. Conventionally, a sheet feeding apparatus has been proposed that includes a side guide plate that regulates the position of a sheet stored in a cassette in the width direction orthogonal to the sheet feeding direction (see Patent Document 1). In this sheet feeding apparatus, the pickup roller is disposed obliquely with respect to the sheet conveyance direction which is the extension direction of the conveyance path, and the sheet is fed while being copied by the side guide plate by the pickup roller. Thus, the sheet is aligned with the side guide plate to reduce the skew of the sheet. There is also known a sheet conveying apparatus provided with a load member which is disposed between the sheet regulating member and the sheet conveying means and applies a load to the sheet (see Patent Document 2).

Japanese Patent Application Laid-Open No. 6-286886 Unexamined-Japanese-Patent No. 2017-114638

  However, the pick-up roller described in the above-mentioned Patent Document 1 needs to simultaneously convey the sheet in the sheet conveyance direction and to have the function of feeding the sheet and the function of pressing the sheet against the side guide plate. There is. For this reason, there has been a problem that the pickup roller can not cope with the feeding of sheets having a wide basis weight and size.

  Further, in the configuration of the sheet conveying apparatus of Patent Document 2, when the sheet is conveyed by the sheet conveying unit, the sheet may be damaged by shear deformation generated between the sheet conveying unit and the load member.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus capable of supporting sheet feeding of a wide range of basis weights and sizes while reducing skew of a sheet, and an image forming apparatus provided with the sheet feeding apparatus.

  According to the present invention, in a sheet feeding apparatus, a sheet stacking unit on which sheets are stacked, and a sheet in a sheet feeding direction is applied by being in contact with the sheets stacked on the sheet stacking unit. A regulation that regulates the position of the end portion, having a feeding rotary body, and an abutting surface capable of abutting on an end portion in a width direction orthogonal to the sheet feeding direction of the sheet stacked on the sheet stacking unit. Means are provided separately from the feeding rotary body, and are in contact with the sheet stacked on the sheet stacking means at the transport upstream side of the feeding rotary body, and are fed by the feeding rotary body And a force applying means for applying a force so that the seat turns.

  According to the present invention, since the force applying means for applying a force which causes the sheet to turn is provided separately from the feeding rotating body for feeding the sheet, the feeding force and the turning force for feeding the sheet can be obtained. It can be set separately. Therefore, it is possible to cope with the feeding of sheets of a wide range of sizes and basis weights. In addition, since the force applying means applies a force to turn the sheet, the sheet can be fed following the contact surface of the restricting means, and the sheet is accurately aligned with the contact surface. Thus, the skew of the sheet can be reduced.

FIG. 1 is an overall schematic view showing a printer according to a first embodiment. FIG. 7A is a side view showing the sheet feeding device in a state in which the middle plate is lowered, and FIG. 7B is a side view showing the sheet feeding device in a state in which the middle plate is raised. FIG. 2 is a plan view showing a sheet feeding apparatus. FIG. (A) is explanatory drawing for demonstrating the feed force and turning force which act on a sheet | seat, (b) is explanatory drawing which shows the component of turning force. (A) is a figure which shows that the clearance gap is vacant between a sheet | seat and a side control guide. (B) is a figure which shows the state which the sheet | seat is turning to CW direction. (C) is a figure which shows the state which the sheet | seat is turning to CCW direction. (D) is a figure which shows the state which is turning so that a sheet | seat may follow a side control guide. (E) is a figure which shows the change of the attitude | position of a sheet | seat. (A) is a figure which shows the sheet | seat of the inclined attitude | position. (B) is a figure which shows the state which the sheet | seat is turning to CW direction. (C) is a figure which shows the state which is turning so that a sheet | seat may follow a side control guide. (D) is a figure which shows the change of the attitude | position of a sheet | seat. (A) is a figure which shows a tab sheet. (B) is a figure which shows the tab sheet loaded in the skewed state. (C) is a figure which shows the tab sheet fed while skewing. FIG. 7 is a side view showing a sheet feeding apparatus according to a second embodiment. FIG. 2 is a plan view showing a sheet feeding apparatus. The perspective view which shows a friction member. Explanatory drawing for demonstrating the feed force and turning force which act on a sheet | seat. FIG. 10 is a plan view showing a sheet feeding apparatus according to a third embodiment. FIG. 14 is a plan view showing a sheet feeding apparatus according to a fourth embodiment. FIG. 14 is a side view showing a sheet feeding apparatus according to a fourth embodiment. The side view which shows the multi feeding apparatus which concerns on 5th Embodiment. The top view which shows a multi feeding apparatus. The perspective view which shows the multi-feed apparatus with which the friction member was applied. The top view which shows the multi feeding apparatus which concerns on 5th Embodiment.

First Embodiment
〔overall structure〕
First, a first embodiment of the present invention will be described. The printer 200 as an image forming apparatus is an electrophotographic laser beam printer, and as shown in FIG. 1, an image forming unit 20 for forming an image on a sheet S, a sheet feeding apparatus 100, and a fixing apparatus 40. ,have. The image forming unit 20 includes four process cartridges 22Y, 22M, 22C, and 22Bk for forming four color toner images of yellow (Y), magenta (M), cyan (C) and black (Bk), respectively, and a scanner unit. And 21.

  The four process cartridges 22Y, 22M, 22C, and 22Bk have the same configuration except that the colors of the images to be formed are different. Therefore, only the configuration of the process cartridge 22Y and the image forming process will be described, and the description of the process cartridges 22M, 22C, and 22Bk will be omitted.

  The process cartridge 22 </ b> Y includes a photosensitive drum 23, a charging roller 24, a developing roller 25, and a cleaning device 27. The photosensitive drum 23 is configured by applying an organic photoconductive layer on the outer periphery of an aluminum cylinder, and is rotated by a drive motor (not shown). Further, in the image forming unit 20, an intermediate transfer belt 31 which is rotated by a drive roller 32 is provided, and inside the intermediate transfer belt 31, primary transfer rollers 26Y, 26M, 26C, 26Bk are provided.

  The fixing device 40 includes a fixing film 41 heated by a heater as a heating unit, and a pressure roller 42 in pressure contact with the fixing film 41. The sheet feeding apparatus 100 is provided at a lower portion of the printer 200, and includes a cassette 106 for storing the sheet, and a feeding unit 10 for feeding the sheet.

  Next, an image forming operation of the printer 200 configured as described above will be described. When an image signal is input to the scanner unit 21 from a personal computer (not shown) or the like, a laser beam corresponding to the image signal is irradiated from the scanner unit 21 onto the photosensitive drum 23 of the process cartridge 22Y.

  At this time, the surface of the photosensitive drum 23 is uniformly charged in advance to a predetermined polarity and potential by the charging roller 24, and the electrostatic latent image is formed on the surface by the laser light being emitted from the scanner unit 21. . The electrostatic latent image formed on the photosensitive drum 23 is developed by the developing roller 25, and a yellow (Y) toner image is formed on the photosensitive drum 23.

  Similarly, the photosensitive drums of the process cartridges 22M, 22C and 22Bk are also irradiated with laser light from the scanner unit 21, and toner images of magenta (M), cyan (C) and black (Bk) are formed on the respective photosensitive drums. Be done. The toner images of the respective colors formed on the respective photosensitive drums are transferred onto the intermediate transfer belt 31 by the primary transfer rollers 26Y, 26M, 26C, 26Bk, and are conveyed to the secondary transfer roller 33 by the intermediate transfer belt 31 rotated by the drive roller 32. It is transported.

  The image forming process of each color is performed at the timing of being superimposed on the upstream toner image primarily transferred onto the intermediate transfer belt 31. Further, after the toner images of the respective colors are transferred to the intermediate transfer belt 31, the toner remaining on the surface of the photosensitive drum 23 is removed by the cleaning device 27.

  In parallel with the image forming process, the sheet S accommodated in the cassette 106 of the sheet feeding apparatus 100 is fed by the feeding unit 10 and then conveyed to the registration roller pair 12. A top sensor 102 is provided upstream of the registration roller pair 12 in the sheet conveyance direction, and the top sensor 102 detects the positions of the leading and trailing ends of the conveyed sheet. The sheet S, the skew of which has been corrected by the registration roller pair 12, is conveyed at a predetermined conveyance timing based on the detection result of the top sensor 102. Then, a full color toner image on the intermediate transfer belt 31 is transferred to the sheet S by the secondary transfer bias applied to the secondary transfer roller 33. The remaining toner remaining on the intermediate transfer belt 31 is collected by the cleaner unit 28.

  The sheet S on which the toner image has been transferred is given predetermined heat and pressure by the fixing film 41 and the pressure roller 42 of the fixing device 40, and the toner is melted and fixed (fixed). The sheet S that has passed through the fixing device 40 is discharged onto the discharge tray 51 by the discharge roller pair 52. An arrow A illustrated in FIG. 1 is an example of a conveyance path along which the sheet S from the cassette 106 to the discharge roller pair 52 is conveyed.

  In addition, the printer 200 has a cover 70 supported openably and closably with respect to the printer main body 71 as an apparatus main body in order to perform jam processing, and a multi-feed device 60. The multi-feed device 60 is used when feeding sheets of irregular size, and a multi-tray 61 for manually feeding a sheet by a user to be stacked, and a multi-feed for feeding sheets stacked on the multi tray 61. And a sending unit 62.

[Sheet feeding device]
As shown in FIG. 2A, the sheet feeding apparatus 100 includes the above-described cassette 106 and the feeding unit 10, and the cassette 106 includes an intermediate plate as a sheet stacking unit on which the sheets S are stacked. 119 is supported so as to be able to move up and down around a rotation center 119a. Below the middle plate 119, a lifter plate 120 is rotatably supported about a rotation center 120a. When the lifter plate 120 ascends, as shown in FIG. 2B, the middle plate 119 ascends, and the sheet S stacked on the middle plate 119 is upstream of the pickup roller 110 of the feeding portion 10 and the pickup roller 110. It abuts on the diagonal feed roller 121 disposed.

  Further, as shown in FIGS. 2A and 2B and FIG. 3, in the cassette 106, side regulating guides 117F and 117R and a rear end regulating guide 118 are provided. The trailing end regulating guide 118 is supported so as to be movable in the sheet feeding direction, and regulates the position of the trailing end which is the upstream end in the sheet feeding direction of the sheet S stacked on the middle plate 119. The rear end restricting guide 118 can be fixed at a position matched to the sheet size by the fixing portion 118L.

  The side regulating guides 117F and 117R as the regulating means have abutment surfaces 117a and 117b which can abut on the end in the width direction orthogonal to the sheet feeding direction of the sheet S stacked on the middle plate 119, It is configured to be slidable in the width direction. Further, the side restriction guides 117F and 117R respectively have interlocking racks 133F and 133R extending in the width direction, and these interlocking racks 133F and 133R are configured to be interlockable by meshing via the pinion gear 134. .

  That is, when the side restriction guide 117F moves to the outside of the cassette 106 in the width direction, the side restriction guide 117R also moves to the outside, and when the side restriction guide 117F moves to the inside of the cassette 106 in the width direction, the side restriction guide 117R also moves to the inside Do. In this manner, the side regulation guides 117F and 117R as the first guide and the second guide are configured such that the positions of both ends in the width direction of the sheets stacked on the middle plate 119 can be regulated by the contact surfaces 117a and 117b. It is done. The side restriction guide 117F is configured to be fixable by the fixing portion 117L.

[Feeding section]
Next, the feeding unit 10 will be described in detail. As shown in FIGS. 2 (a) and 2 (b) and FIG. 3, the feeding unit 10 has a drive shaft 115 to which the driving force of the motor M is input, and a holder 113 rotatably supported by the drive shaft 115. And a pick-up roller shaft 116 rotatably supported by the holder 113. A feed roller 111 and a feed gear 124 are attached to the drive shaft 115.

  The holder 113 rotatably supports an idler shaft 127 to which an idler gear 125 meshing with the feed gear 124 is attached, and a pickup roller gear 126 meshing to the idler gear 125 is attached to the pickup roller shaft 116 There is. Further, a pickup roller 110 as a feeding rotary member and an arm 123 are attached to a pickup roller shaft 116 as a rotation shaft.

  As shown in FIG. 4, a diagonal feed roller 121 as a force applying means, a rotary body or a diagonal feed roller is rotatably supported by the arm 123, and the diagonal feed roller 121 has a core 121a having a shaft portion and , And an outer layer 121b in contact with the sheet S. The outer layer 121 b is made of a material that generates a large frictional force with the sheet S, such as EPDM rubber (ethylene-propylene-diene rubber) or urethane rubber. Further, as shown in FIG. 3, the obliquely feeding roller 121 is disposed to be inclined at an angle θ with respect to the conveyance center line 80 in the width direction of the middle plate 119, and provided separately from the pickup roller 110. . That is, when viewed from the thickness direction of the sheet, the rotational axis 121c of the oblique feed roller 121 is inclined with respect to the width direction (arrow W direction in FIG. 3) orthogonal to the sheet feeding direction (arrow FD in FIG. 3). ing. In addition, although angle (theta) can be set freely, 5-10 degrees are suitable. Further, as shown in FIG. 2A, the outer diameter r2 of the oblique feed roller 121 is set smaller than the outer diameter r1 of the pickup roller 110.

  As shown in FIGS. 2A and 2B, the holder 113 is biased downward by a pickup spring 114 as a first biasing unit, and the arm 123 is a roller spring 122 as a second biasing unit. Is biased downward by That is, the pickup roller 110 is biased toward the sheet stacked on the middle plate 119 by the pickup spring 114 via the holder 113. Further, the diagonal feed roller 121 is biased toward the sheet stacked on the middle plate 119 by the roller spring 122 via the arm 123. A weight may be used instead of the pickup spring 114 and the roller spring 122, and the pickup roller 110 may be biased toward the sheet by the own weight of the pickup roller 110 and the holder 113. Further, the diagonal feed roller 121 may be biased toward the sheet by the weight of the diagonal feed roller 121 and the arm 123.

  Further, as shown in FIG. 3, when the driving force of the motor M is input to the drive shaft 115, the feed roller 111 and the feed gear 124 attached to the drive shaft 115 rotate. The rotation of the feed gear 124 is transmitted to the pickup roller gear 126 via the idler gear 125, and the pickup roller 110 is rotated via the pickup roller shaft 116 by rotation of the pickup roller gear 126. At this time, the rotation directions of the feed roller 111 and the pickup roller 110 are the same.

  Below the feed roller 111, as shown in FIGS. 2 (a) and 2 (b), a separation roller 112, which forms a nip 128 with the feed roller 111, is disposed, and the separation roller 112 has a torque limiter (not shown). It is attached. By the action of the torque limiter, sheets entering the nip 128 are separated one by one. Note that rotational driving in the direction opposite to the sheet feeding direction may be input to the separation roller 112.

  As shown in FIG. 2A, when the motor M (see FIG. 3) rotates with the pickup roller 110 and the oblique feeding roller 121 in contact with the sheet S, the sheet S is moved by the pickup roller 110 and the oblique feeding roller 121. It is fed. The sheet S fed by the pickup roller 110 and the oblique feeding roller 121 is separated one by one by the nip 128 formed by the feed roller 111 and the separation roller 112, and is directed to the registration roller pair 11 (see FIG. 1). It is transported.

[Force acting on sheet]
Next, the force acting on the sheet S when the sheet feeding operation is started will be described. As shown in FIG. 5A, the pickup roller 110 contacts the sheet S at the contact point P1 as the second contact portion and the fourth contact portion, and the oblique feeding roller 121 contacts the sheet S. It abuts on a contact point P2 as a first contact portion. Assuming that the force received by the sheet S at the contact point P1 is F1 and the force received at the contact point P2 is F2, F1 and F2 can be expressed as follows.
F1 = μ1 × N1
F2 = μ2 × N2

  Here, μ1 is the coefficient of friction between the sheet S and the pickup roller 110, and N1 is the pressing force of the pickup roller 110 against the sheet S at the contact point P1. μ 2 is the coefficient of friction between the sheet S and the oblique feed roller 121, and N 2 is the pressing force of the oblique feed roller 121 against the sheet S at the contact point P 2. Also, the directions of F1 and F2 are vector directions indicated by arrows in FIG. 5 (a).

  As shown in FIG. 5B, the force F2 can be decomposed into F2 sin θ, which is a force along the transport center line 80, and F2 cos θ, which is along the width direction. Of the force F2 applied to the sheet S by the oblique feed roller 121, the sheet S is rotated by the force F2 cos θ. That is, the sheet S tries to move in the sheet feeding direction by the force F1 which is a feeding force by the pickup roller 110, but since the force F2 cos θ acts at the contact point P2, the CW direction is substantially centered on the contact point P1. It moves in the sheet feeding direction while turning. Therefore, when the sheet S is fed by the pickup roller 110 and the oblique feeding roller 121, it tends to change from the attitude shown by the solid line in FIG. 5A to the attitude shown by the broken line. Hereinafter, F1 is referred to as a feeding force, and F2 is referred to as a turning force. Further, the conveyance center line 80 is a straight line connecting the contact point P1 and the contact point P2, and extends parallel to the sheet feeding direction.

[Position change of seat]
Next, how the sheet S is fed while being changed in posture in accordance with the stacking condition of the sheet S will be specifically described. First, the case where there is a gap between the side regulating guides 117F and 117R and the sheet S will be described. The side regulating guides 117F and 117R move in accordance with a sheet of a fixed size such as A3, A4, A5, LTR, LGL, etc., and can be fixed by the fixing portion 117L. Generally, in order to cope with sheet setability improvement and sheet size variation, the side restriction guides 117F and 117R are generally positioned with a gap about 1 to 2 mm wider than the sheet width of the fixed size. is there.

  Then, as shown in FIG. 6A, a gap is opened between the side regulating guides 117F and 117R and the sheet S. In the case of a sheet feeding apparatus of a type in which the sheet S is fed by applying only the feeding force (the force F1 in the present embodiment) to the sheet S, when the sheet S is set or during the feeding operation The posture of the sheet varies by this gap, which causes skew.

  Changes in the posture of the sheet S in the present embodiment are shown in FIGS. 6B to 6D, but in each of the drawings, the posture shown by the solid line is changed to the posture shown by the broken line. In the present embodiment, in addition to the feeding force F1 applied by the pick-up roller to the sheet S, the turning force F2 is applied by the oblique feeding roller 121, so the sheet S is shown in FIG. As shown in FIG. 2, the sheet is fed while being swung in the CW direction. Then, the end portion 81 in the width direction of the sheet S collides with the upstream end 117Ra in the sheet feeding direction of the contact surface 117b of the side regulating guide 117R. Thus, the turning operation in the CW direction centering on the vicinity of the contact point P1 of the sheet S is inhibited by the upstream end 117Ra.

  When the sheet S is further fed, as shown in FIG. 6C, the sheet S moves in the CCW direction opposite to the CW direction centering on the upstream end 117Ra of the contact surface 117b by the turning force F2. To turn. Then, as shown in FIG. 6D, the end 81 of the sheet S in the width direction follows the contact surface 117b, and the end 81 and the contact surface 117b become parallel.

  That is, as shown in FIG. 6E, the sheet S moves in the order of the posture S (a), the posture S (b), the posture S (c) and the posture S (d), and finally the sheet S The end 81 is fed parallel to the contact surface 117b. Thereby, the skew of the sheet S is reduced.

  Next, as shown in FIG. 7A, a case will be described in which the sheet S stacked on the middle plate 119 is fed such that the rear end is inclined toward the front side of the apparatus, that is, the side regulating guide 117F. Changes in the posture of the sheet S in the present embodiment are shown in FIGS. 7B and 7C, but in each of the drawings, the posture shown by the solid line is changed to the posture shown by the broken line.

  When the sheet feeding operation is started, as shown in FIG. 7B, the sheet S is fed while rotating in the CW direction around the vicinity of the contact point P1. As a result, the rear end of the sheet inclined to the front side of the apparatus moves to the rear side of the apparatus, and the end 81 of the sheet S in the width direction follows the contact surface 117b as shown in FIG. The portion 81 and the contact surface 117b are parallel to each other.

  That is, as shown in FIG. 7D, the sheet S moves in the order of the posture S (e), the posture S (f) and the posture S (g), and finally the end 81 of the sheet S abuts It is fed parallel to the surface 117b. Thereby, the skew of the sheet S is reduced.

  When the posture of the sheet S before the start of the sheet feeding operation is a posture in which the rear end is inclined to the rear side of the apparatus, as shown in FIG. 6C, FIG. 6C and FIG. Since the sheet S is pivoted as described above, the description is omitted.

  As described above, regardless of the posture of the sheet S before the sheet feeding operation starts, the sheet S is fed while being rotated, so that the end of the sheet S on the contact surface 117b of the side regulating guide 117R. The portion 81 can be copied, and the skew of the sheet S can be reduced.

  Further, since the pick-up roller 110 for applying the feeding force F1 to the sheet S and the oblique feeding roller 121 for applying the turning force F2 to the sheet S are independently provided, the feeding force F1 and the turning force F2 can be obtained. Each can be set separately. For this reason, for example, by making the turning force F2 smaller than the feeding force F1, the sheet S is pressed against the side regulating guide 117R with a force stronger than the rigidity of the sheet, and the sheet S is damaged. Can be prevented. In addition, the sheet can be fed with a wide range of sizes and basis weights. The feeding force F1 is set in accordance with the shape of the pickup roller 110 and the biasing force of the pickup roller spring 114. The turning force F2 is set in accordance with the inclination angle and shape of the oblique feeding roller 121 and the biasing force of the roller spring 122.

  Further, in the present embodiment, as shown in FIG. 6A, the diagonal feed roller 121 is disposed such that the contact point P2 is positioned upstream of the downstream end 117Rb in the sheet feeding direction of the contact surface 117b. It is done. When the turning force F2 is applied to the sheet S at a position downstream of the side regulation guide 117R in the sheet feeding direction (for example, a position like the contact point P1), the rear end of the sheet S passes the downstream end 117Rb of the side regulation guide 117R. Then, the sheet S is skewed. Such a configuration can reduce the skew of the sheet S.

  In the present embodiment, no driving force is input to the oblique feeding roller 121, and the oblique feeding roller 121 is driven to rotate with respect to the sheet S. However, even if the driving force is input to the oblique feeding roller 121 Good. However, even if the driving force is input to the oblique feeding roller 121, the effect in the present embodiment does not change at all, and the cost increases because the number of parts for inputting the driving force increases. It is preferable to use a form that is driven to rotate.

  Further, the outer diameter r2 of the oblique feeding roller 121 is set smaller than the outer diameter r1 of the pickup roller 110, and the driving force is not input to the oblique feeding roller 121 as described above, and the number of necessary parts is small. A space for installing the feed roller 121 can be saved. For this reason, the oblique feed roller 121 can be applied to various feeding devices. In particular, the pickup roller 110 and the oblique feed roller 121 in the present embodiment can save a space while the pickup roller itself in which the driving force is input is disposed obliquely to the sheet conveyance direction, and the side restriction guide The 117F and 117R can also be miniaturized.

  Furthermore, the side restriction guides 117F and 117R in the present embodiment may be either the front side or the rear side of the device, and in particular, the tab sheet St as shown in FIGS. 8A to 8C is supplied. It is suitable for sending.

  As shown in FIG. 8A, one end 81 of the tab sheet St in the width direction fully contacts the abutment surface 117b of the side regulating guide 117R, but the tab sheet St contacts the abutment surface 117a of the side regulating guide 117F. Only tab 129 can be touched. For this reason, as shown in FIG. 8B, there is a high possibility that the posture is shifted when setting the tab sheet St. Further, as shown in FIG. 8C, when the tab 129 passes the side regulation guide 117F during feeding, a gap is formed between the side regulation guides 117F and 117R and the tab sheet St, and the tab sheet St is skewed. There is a risk of

  However, in the present embodiment, the side restriction guide for aligning the postures of the sheet S and the tab sheet St may be only the side restriction guide 117R on the rear side of the apparatus. Since the tab sheet St is always fed while being pressed against the contact surface 117b of the side regulating guide 117R, it is possible to reduce the skew of the tab sheet St.

  In the present embodiment, the oblique feed roller 121 is disposed to be inclined so as to press the sheet S against the side regulating guide 117R, but the present invention is not limited to this. For example, the diagonal feed rollers 121 may be arranged symmetrically with respect to the transport center line 80 in the width direction, and the sheet S may be pressed against the side regulating guide 117F. Further, the diagonal feed roller 121 may not be disposed on the transport center line 80.

Second Embodiment
Next, a second embodiment of the present invention will be described. In the second embodiment, a friction member 130 is applied instead of the oblique feed roller 121 of the first embodiment. . For this reason, about the same composition as a 1st embodiment, illustration is omitted, or the same numerals are given to a figure and it explains.

[Friction member]
As shown in FIGS. 9 and 10, the sheet feeding apparatus 100A includes an arm 123 rotatably supported by the pickup roller shaft 116, and a friction spring 131 urging the arm 123 downward. The friction member 130 is provided on the lower surface of the arm 123. As shown in FIG. 11, the friction member 130 as a force applying means has a substantially spherical contact surface, and is configured to be able to abut on the sheet S stacked on the middle plate 119 (see FIG. 9). ing.

  The friction member 130 is biased toward the sheet S by the friction spring 131 via the arm 123, as shown in FIG. Further, as shown in FIG. 10, the friction member 130 is in contact with the sheet S at the contact point P3 as the third contact portion, and the contact point P3 is on the front side of the apparatus with respect to the conveyance center line 80. To the distance L. Therefore, as shown in FIG. 12, a straight line 82 connecting the contact point P1 and the contact point P3 is inclined with respect to the conveyance center line 80 extending in the sheet feeding direction.

[Force acting on sheet]
Next, the force acting on the sheet S when the sheet feeding operation is started will be described. As shown in FIG. 12, the pickup roller 110 contacts the sheet S at the contact point P1, and the friction member 130 contacts the sheet S at the contact point P3. Assuming that the feeding force that the sheet S receives at the contact point P1 is F1 and the turning force that the sheet S receives at the contact point P3 is F3, F1 and F3 can be expressed as follows.
F1 = μ1 × N1
F3 = μ3 × N3

  Here, μ1 is the coefficient of friction between the sheet S and the pickup roller 110, and N1 is the pressing force of the pickup roller 110 against the sheet S at the contact point P1. μ3 is a coefficient of friction between the sheet S and the friction member 130, and N3 is a pressing force of the friction member 130 against the sheet S at the contact point P3. Further, the directions of the feeding force F1 and the turning force F3 are vector directions indicated by arrows in FIG. 12 and are opposite to each other.

  The sheet S tries to move in the sheet feeding direction by the feeding force F1 by the pickup roller 110. However, since the turning force F3 acts at the contact point P3, the sheet S turns in the CW direction about the contact point P1. Move in the feed direction. For this reason, when the sheet S is fed by the pickup roller 110, it tends to change from the attitude shown by the solid line in FIG. 12 to the attitude shown by the broken line.

  As described above, also in the present embodiment, since the feeding force F1 and the turning force F3 are applied to the sheet S from separate members, the feeding force F1 and the turning force F3 should be set separately. Can.

Third Embodiment
Next, a third embodiment of the present invention will be described. In the third embodiment, the friction member of the second embodiment is disposed at another place. For this reason, about the same composition as a 2nd embodiment, illustration is omitted, or the same numerals are given to a figure and it explains.

  As shown in FIG. 13, the sheet feeding apparatus 100B includes side regulation guides 117F and 117R, an arm 132 extending in the width direction from the side regulation guide 117F, and a friction member 140 provided at the tip of the arm 132. doing. The friction member 140 as a force applying means is in contact with the sheet S at the contact point P4, and the contact point P4 is shifted from the conveyance center line 80 by the distance L2 to the front side of the apparatus.

  Also by this friction member 140, a turning force can be applied to the sheet S as in the friction member 130 of the second embodiment. In addition, since the friction member 140 is provided on the arm 132 extending from the side regulating guide 117F, the degree of freedom in the arrangement of the friction member 140 can be improved.

Fourth Embodiment
Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, the friction member of the second embodiment is disposed at another place. For this reason, about the same composition as a 2nd embodiment, illustration is omitted, or the same numerals are given to a figure and it explains.

  FIG. 14 is a view showing a configuration in which the friction member 140 is supported by the housing 711 of the printer main body 71. As shown in FIG. The friction member 140 is in contact with the sheet S at an abutment point P <b> 5 on the upstream side of the pickup roller 110. More specifically, as shown in FIG. 15, the friction member 140 has a downstream end in the sheet conveying direction more than a virtual line I indicating the position of the upstream end of the pickup roller 110, as in the above embodiment. It is located on the upstream side, and is in contact with the sheet at a contact point P5 on the upstream side of the contact point P1 of the pickup roller 110 with the sheet S.

  Further, as shown in FIG. 14, since the friction member 140 is supported by the housing 711 of the printer main body 71 via a spring, the degree of freedom in arrangement is high, and the contact point P5 is in front of the apparatus with respect to the conveyance center 80. It is disposed on the side so as to be offset by a distance L3. In addition, of the pair of opposing side regulation guides 117R and 117F, the sheet supported by the cassette 106 is abutted on the downstream side of the side regulation guide 117F on the side where the friction member 140 is provided. A pressing portion 1171 is provided which presses the side regulating guide 117R. The pressing portion 1171 directs the side end of the sheet supported by the cassette 106 toward the side regulating guide 117R in the sheet width direction by the biasing force of the biasing member interposed between the pressing portion 1171 and the main body of the side regulating guide 117R. It is configured to be energized.

  Because of this configuration, the sheet supported by the cassette 106 is pressed in addition to the action of the pivoting force directed to the side regulating guide 117R at the abutment point P5, as in the second embodiment. By receiving the biasing force from the portion 1171, the side end is transported while being pressed against the contact surface of the side regulating guide 117R. In the present embodiment, the position of the downstream end of the side regulating guides 117R and 117F in the sheet conveying direction is also located upstream of the pickup roller 110.

Fifth Embodiment
Next, a fifth embodiment of the present invention will be described. In the fifth embodiment, the oblique feed roller of the first embodiment is applied to a multi-feed device 60. For this reason, about the same composition as a 1st embodiment, illustration is omitted, or the same numerals are given to a figure and it explains.

  In the present embodiment, as shown in FIGS. 16 and 17, the configuration of the feeding unit 10 described in the first embodiment is applied to a multi feeding device 60 as a sheet feeding device. Therefore, in FIG. 16 and FIG. 17, “A” is attached to the end of each reference numeral shown in FIG. 2 (b) and FIG. 3 for the members that exert the same function as the members described in the first embodiment. And I omit the explanation.

  A sheet S stacked on a multi-tray 61 as sheet stacking means is provided with a feeding force by a pickup roller 110A as a feeding rotary body, and a turning force is applied by an oblique feeding roller 121A. Therefore, the feeding force and the turning force can be set separately.

  Although this embodiment applies the configuration described in the first embodiment to the multi-feed device 60, the configuration described in the second to fourth embodiments is not Of course, it may be applied to the feeding device 60. For example, when the configuration described in the fourth embodiment is applied to the multi-feed device 60, it becomes as shown in FIG. That is, when applied to the multi-feed device 60, the friction member 140A is supported by the housing 711A forming the side portion of the printer main body 71, and the position thereof is the upstream side of the pickup roller 110A in the sheet conveying direction. It is located upstream of the end. Further, among the side regulating guides 117FA and 117RA, a pressing portion 1171A is provided on the side regulating guide 117FA located on the friction member 140A side.

Sixth Embodiment
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, the side restriction guide on one side of the fifth embodiment is replaced with a fixed guide. For this reason, about the same composition as a 5th embodiment, illustration is omitted, or the same numerals are given to a figure and it explains.

  In the first to fifth embodiments, the side restriction guides on both the front and back sides are configured to be movable in the width direction, and the sheet feeding device is a type that feeds the sheet S based on a so-called center reference. . However, the present invention is applicable not only to the central reference sheet feeding device but also to the side abutting reference sheet feeding device.

  FIG. 19 is a plan view showing the side abutment reference multi-feed device 160 according to the present embodiment. The multi-feed device 160 has a fixed guide 1117RA and a side restricting guide 117FA which restrict the positions of the end portions in the width direction of the sheets stacked on the multi-tray 61. Here, assuming that a straight line connecting the contact point P1A between the sheet S and the pickup roller 110A and the contact point P2A between the sheet S and the oblique feeding roller 121A is a straight line 180A, the straight line 180A extends parallel to the sheet feeding direction. ing.

  The side regulation guide 117FA as the fourth guide is provided on the front side of the apparatus with respect to the straight line 180A, and is supported movably in the width direction with respect to the multi tray 61. The fixed guide 1117RA is provided on the rear side of the apparatus with respect to the straight line 180A, and is fixed to the multi tray 61. That is, the fixed guide 1117RA as the third guide can not move relative to the multi tray 61. The sheet S stacked on the multi-tray 61 is applied with a feeding force by the pickup roller 110A, and a turning force is applied by the oblique feeding roller 121A. At this time, the turning force acts so that the sheet S is pressed against the fixed guide 1117RA. That is, the oblique feeding roller 121A is disposed such that the sheet S is pressed against the fixed guide 1117RA by the turning force applied by the oblique feeding roller 121A. In the present embodiment, not the center reference but the side abutment reference, for example, the A5, A4 and A3 size sheets shown in FIG. 16 are each compared to a straight line 180A connecting the contact point P1A and the contact point P2A. It does not have to be arranged symmetrically.

  In any of the embodiments described above, it is desirable that the members (slant feed rollers 121, friction members 130, 140, etc.) that generate the turning force be disposed upstream of the pickup roller 110 in the conveying direction. By arranging the member for generating the turning force on the upstream side of the pickup roller 110 in the conveyance direction, the shear force per unit length acting on the sheet to be conveyed is reduced. The magnitude of the pivoting force acting on the sheet is proportional to the length of the width direction component of the line connecting the position at which the member generating the pivoting force contacts the sheet and the position at which the pickup roller 110 contacts the sheet. On the other hand, the shear force per unit length acting on the sheet is inversely proportional to the length of the aforementioned line segment. The shear force acting on the sheet is generated when the sheet is pulled between the member generating the pivoting force and the pickup roller 110. When the value of the shear force is constant, the shear force generated per unit length of the sheet decreases as the length of the above-mentioned line segment increases.

  Therefore, when the member for generating the turning force is disposed on the upstream side in the conveying direction of the pickup roller 110, the same turning is performed as compared with the case where the member for generating the turning force is shifted in the width direction of the pickup roller 110. The shear force per unit length of the sheet can be reduced while generating the force.

  Further, in any of the embodiments described above, the description has been made using the electrophotographic printer 200, but the present invention is not limited to this. For example, the present invention can be applied to an inkjet type image forming apparatus that forms an image on a sheet by discharging ink liquid from a nozzle. In addition, the present invention may be applied to an ADF (Auto Document Feeder) that automatically conveys a document. Also, the first to sixth embodiments may be combined with each other.

  Furthermore, in the embodiment in which the sheet is rotated using the friction member 140 / 140A described above, the sheet is rotated about the contact point of the pickup roller 110 / 110A, but, for example, with the friction member 140 / 140A The sheet may be configured to be rotated toward the side restriction guide by the conveyance force of the pickup roller 110 / 110A around the contact point.

  20: image forming unit / 60: sheet feeding device (multi feeding device) / 61, 119: sheet stacking means (middle plate, multi tray) / 71: device main body (printer main body) / 80, 80A, 82, 180A : Straight line (conveying center line) / 81: end / 100, 100A, 100B: sheet feeding device / 106: cassette / 110, 110A: feeding rotating body (pickup roller) / 114: first biasing means (pickup Spring) / 117a, 117b: contact surface / 117F: regulating means, first guide (side regulating guide) / 117FA: regulating means, fourth guide (side regulating guide) / 117R: regulating means, second guide (side regulating) Guide) / 117 Rb: downstream end / 121: force applying means, rotating body, oblique feeding roller (oblique feeding roller) / 122: second biasing means (coro spring) / 130, 140 Force application means, friction member / 200: image forming apparatus (printer) / 1117RA: restriction means, fourth guide (fixed guide) / FD: sheet feeding direction / P1: second contact portion, fourth contact portion Current contact point) / P2: first contact portion (contact point) / P3: third contact portion (contact point) / r1, r2: outer diameter / W: width direction

Claims (17)

A sheet stacking unit on which sheets are stacked;
A feeding rotary member that feeds a sheet by applying a feeding force in the sheet feeding direction by contacting the sheet stacked on the sheet stacking unit;
A restricting unit having an abutting surface capable of abutting on an end portion in a width direction orthogonal to the sheet feeding direction of the sheet stacked on the sheet stacking unit, and restricting a position of the end portion;
The sheet is provided separately from the feeding rotary member and abuts against the sheet stacked on the sheet stacking means at the transport upstream side of the feeding rotary member, and the sheet fed by the feeding rotary member is turned And force applying means for applying a force to
Sheet feeding apparatus characterized in that. The force applying unit has a rotating body rotatable around a rotation axis inclined with respect to the width direction as viewed from the thickness direction of the sheets stacked on the sheet stacking unit.
The sheet feeding device according to claim 1, In the rotary body, a first contact portion where the rotary body and the sheet stacked on the sheet stacking unit are in contact is positioned upstream of the downstream end of the contact surface in the sheet feeding direction. Placed,
The sheet feeding device according to claim 2, The rotating body is driven to rotate with respect to a sheet fed by the feeding rotating body.
The sheet feeding device according to claim 2, The feeding rotary body abuts on the sheet stacked on the sheet stacking means at a second contact portion,
A straight line connecting the first contact portion and the second contact portion is parallel to the sheet feeding direction.
The sheet feeding device according to claim 3 or 4, wherein The feed roller is a pickup roller,
The rotating body is an oblique feeding roller disposed upstream of the pickup roller in the sheet feeding direction,
The outer diameter of the oblique feed roller is smaller than the outer diameter of the pickup roller
The sheet feeding device according to any one of claims 3 to 5, characterized in that: A rotating shaft rotatably supporting the pickup roller;
And an arm rotatably supported on the rotation shaft.
The oblique feed roller is rotatably supported by the arm.
7. The sheet feeding device according to claim 6, wherein The force applying means includes a friction member which abuts the sheet stacked on the sheet stacking means at a third contact portion and applies a frictional force to the sheet.
The feeding rotational body abuts on a sheet stacked on the sheet stacking means at a fourth contact portion,
A straight line connecting the third contact portion and the fourth contact portion is inclined with respect to the sheet feeding direction.
The sheet feeding device according to claim 1, The friction member is disposed such that the third contact portion is positioned upstream of a downstream end of the contact surface in the sheet feeding direction.
9. The sheet feeding apparatus according to claim 8, wherein The feed roller is a pickup roller rotatably supported on a rotation shaft,
And an arm rotatably supported by the rotation shaft and supporting the friction member.
10. The sheet feeding apparatus according to claim 8, wherein An arm attached to the restricting means and supporting the friction member;
10. The sheet feeding apparatus according to claim 8, wherein First biasing means for biasing the feed roller toward the sheet stacked on the sheet stacking means;
And second biasing means for biasing the force applying means toward the sheets stacked on the sheet stacking means.
The sheet feeding apparatus according to any one of claims 1 to 11, wherein An apparatus body provided with the feeding rotary body;
And a cassette which can be pulled out with respect to the device body.
The sheet stacking means is supported by the cassette so as to be movable up and down.
The sheet feeding apparatus according to any one of claims 1 to 12, wherein The sheet stacking unit is a tray to which sheets are manually fed.
The sheet feeding apparatus according to any one of claims 1 to 12, wherein The restriction means has a first guide and a second guide that can be interlocked symmetrically with respect to a conveyance center line in the width direction of the sheet stacking means.
The sheet feeding device according to any one of claims 1 to 14, wherein the sheet feeding device is a sheet feeding device. The restriction means includes a third guide which can not move relative to the sheet stacking means, and a fourth guide which is movable relative to the sheet stacking means.
The sheet to which force is applied by the force applying means is pivoted so as to be pressed against the third guide.
The sheet feeding device according to any one of claims 1 to 14, wherein the sheet feeding device is a sheet feeding device. A sheet feeding apparatus according to any one of claims 1 to 16.
An image forming unit that forms an image on a sheet fed by the sheet feeding device;
An image forming apparatus characterized by

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